import java.util.Scanner;

public class Demo02 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        System.out.println("enter your number:");
        int num=scanner.nextInt();
        int flag=0;
        for(int i=2;i<num;i++){
            if(num%i==0){
                flag=1;
                break;
            }else{
                flag=0;
            }
        }
        if(flag==1){
            System.out.println("不是素数");
        }else{
            System.out.println("是素数");
        }
    }
}
